diff --git a/samples/conntest.cpp b/samples/conntest.cpp
index fd2943bf86..80ef6e3639 100644
--- a/samples/conntest.cpp
+++ b/samples/conntest.cpp
@@ -37,7 +37,7 @@ void curlcon(const std::string& url, bool useHttp1_0 = false) {
 
   // get the timeout value
   std::string timeoutStr = Exiv2::getEnv(Exiv2::envTIMEOUT);
-  long timeout = atol(timeoutStr.c_str());
+  long timeout = std::stol(timeoutStr);
   if (timeout == 0) {
     throw Exiv2::Error(Exiv2::ErrorCode::kerErrorMessage, "Timeout Environmental Variable must be a positive integer.");
   }
diff --git a/src/basicio.cpp b/src/basicio.cpp
index 5bbea74579..dd9b188e17 100644
--- a/src/basicio.cpp
+++ b/src/basicio.cpp
@@ -1422,7 +1422,7 @@ int64_t HttpIo::HttpImpl::getFileLength() {
   }
 
   auto lengthIter = response.find("Content-Length");
-  return (lengthIter == response.end()) ? -1 : atol((lengthIter->second).c_str());
+  return (lengthIter == response.end()) ? -1 : std::stoll(lengthIter->second);
 }
 
 void HttpIo::HttpImpl::getDataByRange(size_t lowBlock, size_t highBlock, std::string& response) {
@@ -1560,7 +1560,7 @@ CurlIo::CurlImpl::CurlImpl(const std::string& url, size_t blockSize) : Impl(url,
   }
 
   std::string timeout = getEnv(envTIMEOUT);
-  timeout_ = atol(timeout.c_str());
+  timeout_ = std::stol(timeout);
   if (timeout_ == 0) {
     throw Error(ErrorCode::kerErrorMessage, "Timeout Environmental Variable must be a positive integer.");
   }
diff --git a/src/crwimage_int.cpp b/src/crwimage_int.cpp
index aebbb07a02..0ea190119f 100644
--- a/src/crwimage_int.cpp
+++ b/src/crwimage_int.cpp
@@ -544,9 +544,11 @@ CiffComponent* CiffDirectory::doAdd(CrwDirs& crwDirs, uint16_t crwTagId) {
     auto dir = crwDirs.top();
     crwDirs.pop();
     // Find the directory
-    auto it = std::find_if(components_.begin(), components_.end(), [=](const auto& c) { return c->tag() == dir.dir; });
-    if (it != components_.end())
-      cc_ = *it;
+    for (const auto& c : components_)
+      if (c->tag() == dir.dir) {
+        cc_ = c;
+        break;
+      }
     if (!cc_) {
       // Directory doesn't exist yet, add it
       m_ = std::make_unique<CiffDirectory>(dir.dir, dir.parent);
@@ -557,10 +559,11 @@ CiffComponent* CiffDirectory::doAdd(CrwDirs& crwDirs, uint16_t crwTagId) {
     cc_ = cc_->add(crwDirs, crwTagId);
   } else {
     // Find the tag
-    auto it =
-        std::find_if(components_.begin(), components_.end(), [=](const auto& c) { return c->tagId() == crwTagId; });
-    if (it != components_.end())
-      cc_ = *it;
+    for (const auto& c : components_)
+      if (c->tagId() == crwTagId) {
+        cc_ = c;
+        break;
+      }
     if (!cc_) {
       // Tag doesn't exist yet, add it
       m_ = std::make_unique<CiffEntry>(crwTagId, tag());
diff --git a/src/datasets.cpp b/src/datasets.cpp
index 00fc47e5b9..8f1f4e9a07 100644
--- a/src/datasets.cpp
+++ b/src/datasets.cpp
@@ -11,6 +11,8 @@
 #include "i18n.h"  // NLS support.
 #include "types.hpp"
 
+#include "image_int.hpp"
+
 #include <array>
 #include <iomanip>
 #include <sstream>
@@ -410,9 +412,7 @@ std::string IptcDataSets::dataSetName(uint16_t number, uint16_t recordId) {
   if (int idx = dataSetIdx(number, recordId); idx != -1)
     return records_[recordId][idx].name_;
 
-  std::ostringstream os;
-  os << "0x" << std::setw(4) << std::setfill('0') << std::right << std::hex << number;
-  return os.str();
+  return stringFormat("0x{:04x}", number);
 }
 
 const char* IptcDataSets::dataSetTitle(uint16_t number, uint16_t recordId) {
@@ -462,9 +462,7 @@ std::string IptcDataSets::recordName(uint16_t recordId) {
     return recordInfo_[recordId].name_;
   }
 
-  std::ostringstream os;
-  os << "0x" << std::setw(4) << std::setfill('0') << std::right << std::hex << recordId;
-  return os.str();
+  return stringFormat("0x{:04x}", recordId);
 }
 
 const char* IptcDataSets::recordDesc(uint16_t recordId) {
diff --git a/src/minoltamn_int.cpp b/src/minoltamn_int.cpp
index 3192a037b9..9f180b1ca3 100644
--- a/src/minoltamn_int.cpp
+++ b/src/minoltamn_int.cpp
@@ -4,6 +4,7 @@
 #include "minoltamn_int.hpp"
 #include "exif.hpp"
 #include "i18n.h"  // NLS support.
+#include "image_int.hpp"
 #include "makernote_int.hpp"
 #include "tags_int.hpp"
 #include "value.hpp"
@@ -331,17 +332,15 @@ std::ostream& MinoltaMakerNote::printMinoltaFocalLengthStd(std::ostream& os, con
 
 std::ostream& MinoltaMakerNote::printMinoltaDateStd(std::ostream& os, const Value& value, const ExifData*) {
   // From the PHP JPEG Metadata Toolkit
-  os << value.toInt64() / 65536 << ":" << std::right << std::setw(2) << std::setfill('0')
-     << (value.toInt64() - value.toInt64() / 65536 * 65536) / 256 << ":" << std::right << std::setw(2)
-     << std::setfill('0') << value.toInt64() % 256;
+  auto val = value.toInt64();
+  os << stringFormat("{}:{:02}:{:02}", val / 65536, (val % 65536) / 256, val % 256);
   return os;
 }
 
 std::ostream& MinoltaMakerNote::printMinoltaTimeStd(std::ostream& os, const Value& value, const ExifData*) {
   // From the PHP JPEG Metadata Toolkit
-  os << std::right << std::setw(2) << std::setfill('0') << value.toInt64() / 65536 << ":" << std::right << std::setw(2)
-     << std::setfill('0') << (value.toInt64() - value.toInt64() / 65536 * 65536) / 256 << ":" << std::right
-     << std::setw(2) << std::setfill('0') << value.toInt64() % 256;
+  auto val = value.toInt64();
+  os << stringFormat("{:02}:{:02}:{:02}", val / 65536, (val % 65536) / 256, val % 256);
   return os;
 }
 
diff --git a/src/nikonmn_int.cpp b/src/nikonmn_int.cpp
index b683010e83..d9b8e49be2 100644
--- a/src/nikonmn_int.cpp
+++ b/src/nikonmn_int.cpp
@@ -5,6 +5,7 @@
 
 #include "exif.hpp"
 #include "i18n.h"  // NLS support.
+#include "image_int.hpp"
 #include "makernote_int.hpp"
 #include "tags_int.hpp"
 #include "utils.hpp"
@@ -3299,10 +3300,9 @@ std::ostream& Nikon3MakerNote::printLensId(std::ostream& os, const Value& value,
       // #1034
       const std::string undefined("undefined");
       const std::string section("nikon");
-      std::ostringstream lensIDStream;
-      lensIDStream << static_cast<int>(raw[7]);
-      if (Internal::readExiv2Config(section, lensIDStream.str(), undefined) != undefined) {
-        return os << Internal::readExiv2Config(section, lensIDStream.str(), undefined);
+      auto lensIDStream = std::to_string(raw[7]);
+      if (Internal::readExiv2Config(section, lensIDStream, undefined) != undefined) {
+        return os << Internal::readExiv2Config(section, lensIDStream, undefined);
       }
     }
 
@@ -3898,10 +3898,9 @@ std::ostream& Nikon3MakerNote::printTimeZone(std::ostream& os, const Value& valu
   std::ostringstream oss;
   oss.copyfmt(os);
   char sign = value.toInt64() < 0 ? '-' : '+';
-  long h = static_cast<long>(std::abs(static_cast<int>(value.toFloat() / 60.0F))) % 24;
-  long min = static_cast<long>(std::abs(static_cast<int>(value.toFloat() - (h * 60)))) % 60;
-  os << std::fixed << "UTC " << sign << std::setw(2) << std::setfill('0') << h << ":" << std::setw(2)
-     << std::setfill('0') << min;
+  long h = static_cast<long>(std::fabs<int>(value.toFloat() / 60.0F)) % 24;
+  long min = static_cast<long>(std::fabs<int>(value.toFloat() - (h * 60))) % 60;
+  os << stringFormat("UTC {}{:02}:{:02}", sign, h, min);
   os.copyfmt(oss);
   os.flags(f);
   return os;
diff --git a/src/panasonicmn_int.cpp b/src/panasonicmn_int.cpp
index 726859f514..b51c17199b 100644
--- a/src/panasonicmn_int.cpp
+++ b/src/panasonicmn_int.cpp
@@ -3,6 +3,7 @@
 // included header files
 #include "panasonicmn_int.hpp"
 #include "i18n.h"  // NLS support.
+#include "image_int.hpp"
 #include "tags_int.hpp"
 #include "types.hpp"
 #include "value.hpp"
@@ -619,9 +620,7 @@ std::ostream& PanasonicMakerNote::print0x0029(std::ostream& os, const Value& val
   std::ostringstream oss;
   oss.copyfmt(os);
   const auto time = value.toInt64();
-  os << std::setw(2) << std::setfill('0') << time / 360000 << ":" << std::setw(2) << std::setfill('0')
-     << (time % 360000) / 6000 << ":" << std::setw(2) << std::setfill('0') << (time % 6000) / 100 << "." << std::setw(2)
-     << std::setfill('0') << time % 100;
+  os << stringFormat("{:02}:{:02}:{:02}.{:02}", time / 360000, (time % 360000) / 6000, (time % 6000) / 100, time % 100);
   os.copyfmt(oss);
 
   return os;
diff --git a/src/pentaxmn_int.cpp b/src/pentaxmn_int.cpp
index 78b32ee47b..87b0d283fb 100644
--- a/src/pentaxmn_int.cpp
+++ b/src/pentaxmn_int.cpp
@@ -4,6 +4,7 @@
 #include "pentaxmn_int.hpp"
 #include "exif.hpp"
 #include "i18n.h"  // NLS support.
+#include "image_int.hpp"
 #include "makernote_int.hpp"
 #include "tags.hpp"
 #include "types.hpp"
@@ -915,21 +916,14 @@ std::ostream& PentaxMakerNote::printResolution(std::ostream& os, const Value& va
 
 std::ostream& PentaxMakerNote::printDate(std::ostream& os, const Value& value, const ExifData*) {
   /* I choose same format as is used inside EXIF itself */
-  os << ((static_cast<uint16_t>(value.toInt64(0)) << 8) + value.toInt64(1));
-  os << ":";
-  os << std::setw(2) << std::setfill('0') << value.toInt64(2);
-  os << ":";
-  os << std::setw(2) << std::setfill('0') << value.toInt64(3);
+  os << stringFormat("{}:{:02}:{:02}", ((static_cast<uint16_t>(value.toInt64(0)) << 8) + value.toInt64(1)),
+                     value.toInt64(2), value.toInt64(3));
   return os;
 }
 
 std::ostream& PentaxMakerNote::printTime(std::ostream& os, const Value& value, const ExifData*) {
   std::ios::fmtflags f(os.flags());
-  os << std::setw(2) << std::setfill('0') << value.toInt64(0);
-  os << ":";
-  os << std::setw(2) << std::setfill('0') << value.toInt64(1);
-  os << ":";
-  os << std::setw(2) << std::setfill('0') << value.toInt64(2);
+  os << stringFormat("{:02}:{:02}:{:02}", value.toInt64(0), value.toInt64(1), value.toInt64(2));
   os.flags(f);
   return os;
 }
diff --git a/src/sonymn_int.cpp b/src/sonymn_int.cpp
index 6510fc8f8d..363b0a6fd5 100644
--- a/src/sonymn_int.cpp
+++ b/src/sonymn_int.cpp
@@ -6,6 +6,7 @@
 #include "error.hpp"
 #include "exif.hpp"
 #include "i18n.h"  // NLS support.
+#include "image_int.hpp"
 #include "minoltamn_int.hpp"
 #include "tiffcomposite_int.hpp"
 #include "utils.hpp"
@@ -1239,10 +1240,8 @@ std::ostream& SonyMakerNote::printPixelShiftInfo(std::ostream& os, const Value&
 
   std::ios::fmtflags f(os.flags());
 
-  os << "Group " << std::setw(2) << std::setfill('0') << ((groupID >> 17) & 0x1f) << std::setw(2) << std::setfill('0')
-     << ((groupID >> 12) & 0x1f) << std::setw(2) << std::setfill('0') << ((groupID >> 6) & 0x3f) << std::setw(2)
-     << std::setfill('0') << (groupID & 0x3f);
-
+  os << stringFormat("Group {:02}{:02}{:02}{:02}", (groupID >> 17) & 0x1f, (groupID >> 12) & 0x1f,
+                     (groupID >> 6) & 0x3f, groupID & 0x3f);
   os << ", Shot " << value.toUint32(4) << "/" << value.toUint32(5) << " (0x" << std::hex << (groupID >> 22) << ")";
   os.flags(f);
   return os;
diff --git a/src/tags.cpp b/src/tags.cpp
index 2426c0bcfc..5b1c4ce161 100644
--- a/src/tags.cpp
+++ b/src/tags.cpp
@@ -46,9 +46,7 @@ constexpr SectionInfo sectionInfo[] = {
 
 namespace Exiv2::Internal {
 bool TagVocabulary::operator==(const std::string& key) const {
-  if (strlen(voc_) > key.size())
-    return false;
-  return 0 == strcmp(voc_, key.c_str() + key.size() - strlen(voc_));
+  return key.rfind(voc_) != std::string::npos;
 }
 
 // Unknown Tag
diff --git a/src/value.cpp b/src/value.cpp
index ee86d8557d..298370293a 100644
--- a/src/value.cpp
+++ b/src/value.cpp
@@ -8,6 +8,8 @@
 #include "error.hpp"
 #include "types.hpp"
 
+#include "image_int.hpp"
+
 // + standard includes
 #include <sstream>
 
@@ -841,8 +843,7 @@ DateValue* DateValue::clone_() const {
 std::ostream& DateValue::write(std::ostream& os) const {
   // Write DateValue in ISO 8601 Extended format: YYYY-MM-DD
   std::ios::fmtflags f(os.flags());
-  os << std::setw(4) << std::setfill('0') << date_.year << '-' << std::right << std::setw(2) << std::setfill('0')
-     << date_.month << '-' << std::setw(2) << std::setfill('0') << date_.day;
+  os << stringFormat("{:04}-{:02}-{:02}", date_.year, date_.month, date_.day);
   os.flags(f);
   return os;
 }
@@ -1023,9 +1024,8 @@ std::ostream& TimeValue::write(std::ostream& os) const {
     plusMinus = '-';
 
   std::ios::fmtflags f(os.flags());
-  os << std::right << std::setw(2) << std::setfill('0') << time_.hour << ':' << std::setw(2) << std::setfill('0')
-     << time_.minute << ':' << std::setw(2) << std::setfill('0') << time_.second << plusMinus << std::setw(2)
-     << std::setfill('0') << abs(time_.tzHour) << ':' << std::setw(2) << std::setfill('0') << abs(time_.tzMinute);
+  os << stringFormat("{:02}:{:02}:{:02}{}{:02}:{:02}", time_.hour, time_.minute, time_.second, plusMinus,
+                     std::abs(time_.tzHour), std::abs(time_.tzMinute));
   os.flags(f);
 
   return os;
diff --git a/src/xmpsidecar.cpp b/src/xmpsidecar.cpp
index 172c389047..875bbe16b8 100644
--- a/src/xmpsidecar.cpp
+++ b/src/xmpsidecar.cpp
@@ -13,8 +13,8 @@
 #include <iostream>
 
 namespace {
-constexpr auto xmlHeader = "<?xpacket begin=\"\xef\xbb\xbf\" id=\"W5M0MpCehiHzreSzNTczkc9d\"?>\n";
-const auto xmlHdrCnt = static_cast<long>(std::strlen(xmlHeader));  // without the trailing 0-character
+constexpr char xmlHeader[] = "<?xpacket begin=\"\xef\xbb\xbf\" id=\"W5M0MpCehiHzreSzNTczkc9d\"?>\n";
+constexpr auto xmlHdrCnt = std::size(xmlHeader) - 1;  // without the trailing 0-character
 constexpr auto xmlFooter = "<?xpacket end=\"w\"?>";
 }  // namespace